how to add form validation using jquery code example

Example 1: form validation using jquery

<script src="https://cdn.jsdelivr.net/jquery.validation/1.16.0/jquery.validate.min.js"></script>
then add javascript code:
$(document).ready(function() {
   $("#form").validate();
});
</script>

Example 2: jquery form validation

function submitFunction(event){
	event.preventDefault();
}
$("#form_id").submit(submitFunction);